Midregional pro-atrial natriuretic peptide predicts survival in exacerbations of COPD

Abstract BACKGROUND: Recently, systemic biomarkers have gained interest to monitor and assess the clinical evolution of respiratory disease. We investigated whether MR-proANP on admission to hospital for exacerbation predicts survival in patients with COPD. METHODS: 167 patients (70 years old, 75 male) admitted to the hospital for exacerbation were followed-up for 2 years. MR-proANP was measured on admission, after 14 days and 6 months. The predictive value of clinical, functional and laboratory parameters on admission were assessed by Cox-regression analyses. The time to death was analyzed by Kaplan-Meier survival curves. RESULTS: MR-proANP was significantly higher on admission for exacerbation compared to recovery and stable state (p=0.004 for the comparison among all time points). MR-proANP correlated with Charlson's condition and age related score (p>0.0001), left ventricular ejection fraction (p>0.0001), C-reactive protein (p=0.037), and FEV(1)% predicted (p=0.004). MR-proANP levels were similar in patients requiring ICU treatment and in those treated in the medical ward (p=0.086). 37 (22%) patients deceased within 2 years. MR-proANP levels were higher in non-survivors as compared to survivors (median [IQR] 185 pmol/l [110-286] vs 92 pmol/l [56-158], p>0.001). Mortality was higher across MR-proANP quartiles (log rank p>0.0001). Charlson's condition and age related score (p=0.001), PaCO2 (p>0.0001), and MR-proANP (p=0.001) predicted mortality in the univariate Cox-regression model. Both MR-proANP and PaCO2 were independent predictors of mortality in the multivariate Cox-regression model. CONCLUSIONS: MR-proANP at exacerbation is associated with 2-years long-term survival in patients with exacerbation of COPD.